### MemCache
# memcache-client 1.5.0
def set(key, value, expiry = 0, raw = false)
  raise MemCacheError, "Update of readonly cache" if @readonly
  server, cache_key = request_setup key
  socket = server.socket

  value = Marshal.dump value unless raw
  command = "set #{cache_key} 0 #{expiry} #{value.size}\r\n#{value}\r\n"

  begin
    @mutex.lock if @multithread
    socket.write command
    result = socket.gets
    raise MemCacheError, $1.strip if result =~ /^SERVER_ERROR (.*)/
  rescue SocketError, SystemCallError, IOError => err
    server.close
    raise MemCacheError, err.message
  ensure
    @mutex.unlock if @multithread
  end
end